Phenotyping analysis of rice cv. Nipponbare overexpressing OsMADS56 gene in drought tolerance, plant height, and...

The MADS-box protein family is a transcription factor (TF) family whose members harbour a MADS-box domain located in their N-terminal. This domain consists of 60 amino acids and functions in DNA binding. In plants, these family genes broadly regulate plant growth, development and responses to various environmental stresses. In this study, an OsMADS56 (702 bp) was isolated from rice (Oryza sativa cv. Nipponbare) to investigate its role in response to drought stress and other agronomic phenotypes at both the vegetative and generative stages.

Rice mutants harbouring overexpressed OsMADS56 gene driven by the constitutive 35S promoter were generated. Quantitative real-time (qRT)-PCR confirmed the overexpression of OsMADS56 at T1 (M76.7) generation. Observation of the T2 OsMADS56-overexpressed rice line (OX7) showed improved tolerance to drought stress. It also showed different agronomic phenotypes compared to wild type (WT), such as shorter plant height (PH) and improved productivity as indicated by earlier heading date (HD), a higher number of panicles (NP), a higher number of grains (NG) and higher grain yield (GY) than WT.

The findings suggest that OsMADS56 was implicated in the rice response to PEG-induced drought stress, rice plant height, and yield components. The OsMADS56 gene and the characterized line can be utilized in further studies on rice adaptation against abiotic stress and its productivity.